/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.scripting;

import java.io.IOException;

import org.springframework.lang.Nullable;

/**
 * Script definition interface, encapsulating the configuration
 * of a specific script as well as a factory method for
 * creating the actual scripted Java {@code Object}.
 *
 * @author Juergen Hoeller
 * @author Rob Harrop
 * @see #getScriptSourceLocator
 * @see #getScriptedObject
 * @since 2.0
 */
public interface ScriptFactory {

    /**
     * Return a locator that points to the source of the script.
     * Interpreted by the post-processor that actually creates the script.
     * <p>Typical supported locators are Spring resource locations
     * (such as "file:C:/myScript.bsh" or "classpath:myPackage/myScript.bsh")
     * and inline scripts ("inline:myScriptText...").
     *
     * @return the script source locator
     * @see org.springframework.scripting.support.ScriptFactoryPostProcessor#convertToScriptSource
     * @see org.springframework.core.io.ResourceLoader
     */
    String getScriptSourceLocator();

    /**
     * Return the business interfaces that the script is supposed to implement.
     * <p>Can return {@code null} if the script itself determines
     * its Java interfaces (such as in the case of Groovy).
     *
     * @return the interfaces for the script
     */
    @Nullable
    Class<?>[] getScriptInterfaces();

    /**
     * Return whether the script requires a config interface to be
     * generated for it. This is typically the case for scripts that
     * do not determine Java signatures themselves, with no appropriate
     * config interface specified in {@code getScriptInterfaces()}.
     *
     * @return whether the script requires a generated config interface
     * @see #getScriptInterfaces()
     */
    boolean requiresConfigInterface();

    /**
     * Factory method for creating the scripted Java object.
     * <p>Implementations are encouraged to cache script metadata such as
     * a generated script class. Note that this method may be invoked
     * concurrently and must be implemented in a thread-safe fashion.
     *
     * @param scriptSource     the actual ScriptSource to retrieve
     *                         the script source text from (never {@code null})
     * @param actualInterfaces the actual interfaces to expose,
     *                         including script interfaces as well as a generated config interface
     *                         (if applicable; may be {@code null})
     * @return the scripted Java object
     * @throws IOException                if script retrieval failed
     * @throws ScriptCompilationException if script compilation failed
     */
    @Nullable
    Object getScriptedObject(ScriptSource scriptSource, @Nullable Class<?>... actualInterfaces)
            throws IOException, ScriptCompilationException;

    /**
     * Determine the type of the scripted Java object.
     * <p>Implementations are encouraged to cache script metadata such as
     * a generated script class. Note that this method may be invoked
     * concurrently and must be implemented in a thread-safe fashion.
     *
     * @param scriptSource the actual ScriptSource to retrieve
     *                     the script source text from (never {@code null})
     * @return the type of the scripted Java object, or {@code null}
     * if none could be determined
     * @throws IOException                if script retrieval failed
     * @throws ScriptCompilationException if script compilation failed
     * @since 2.0.3
     */
    @Nullable
    Class<?> getScriptedObjectType(ScriptSource scriptSource)
            throws IOException, ScriptCompilationException;

    /**
     * Determine whether a refresh is required (e.g. through
     * ScriptSource's {@code isModified()} method).
     *
     * @param scriptSource the actual ScriptSource to retrieve
     *                     the script source text from (never {@code null})
     * @return whether a fresh {@link #getScriptedObject} call is required
     * @see ScriptSource#isModified()
     * @since 2.5.2
     */
    boolean requiresScriptedObjectRefresh(ScriptSource scriptSource);

}
